A separate proteomic analysis has also been completed using mass spectrospcopy in tandem with whole stage-specific tryptic digestion. Not only has the stage specific proteomes been completed for adult males, adult females, microfilariae, and infective larvae, but we have also completed the Brugia Wolbachia proteome and the excretory/secretory proteome. These analyses have provided clear evidence that those genes encoding hypothetical proteins are real and have also identified close to 70% of all predicted open reading frames. Further the secretome analyses have revealed unexpected secreted proteins many of which have host-immunomodulatory properties. Using phage display libraries (from infective larvae L3 and adult females) Brugia malayi and screens with known soluble human receptors, we have identified, cloned and characterized distinct molecules that bind to the human IL-5R, IL-10R, and IL-13R. The molecule we term, Bm-IL5RBP Brugia malayi IL5Rbinding protein(IL5Rbp) has been expressed at high levels in a manner that retains its ability to bind to the human receptor. Antibodies raised to predicted immunogenic peptides inhibit the binding of rBm-IL5BP to its human receptor and have been used to localize (by immuno-EM) Bm-IL5RBP to the surface of the infective stage larvae. The rBm-IL5BP does not itself prolong the survival of human eosinophils, but does inhibit the ability of human IL5 to prolong eosinophil survival. Interestingly, we have also identified a secreted product from Brugia malayi L3 that is chemotactic for human eosinophils. This secreted products signals through the G-coupled receptor CXCR3. The molecular differences between non-infective first-stage (L1) and infective third-stage larvae (L3i) of the parasitic nematode Strongyloides stercoralis (Ss) were assessed using newly developed DNA microarrays. 967 differentially expressed genes (457 L3i-specific; 510 L1-specific) were identified. Based on a functional analysis of these genes, L1s have an increased number of genes putatively involved in transcription (p=0.0158) and L3is have increased expression of stress-related genes (such as putative heat shock proteins dnj-12, daf-21, dnj-10). Immunoreactive genes (SsIR and NIE) were additionally found to be L3i-specific. Unique and abundant L3i contigs of interest included the Ss orthologs of a cytochrome oxidase ucr 2.1, daf-12 and daf-21, which may be potential chemotherapeutic targets. The Ss ortholog of fatty acid and retinol binding protein-1, which has been successfully used in a vaccine against Ancylostoma ceylanicum, was identified among the top 25 upregulated L3i genes. The sperm containing glycoprotein domain, utilized in a vaccine against the nematode Cooperia punctata, was exclusively found in the L3i group, and may additionally be a valuable Ss target of interest. An expanded approach to protective immunity in both filarial infections and in strongyloides is underway. Antigens affinity purified using sera from either mice immunized with irradiated larvae that show close to 100% protection to challenge infection with S. strongyloides or humans demonstrating immunity to Ss infection have identified 6 candidates that have been expressed in E. coli, yeast and baculovirus. Testing with one baculovirus-derived recombinant has provided 70% protection in a mouse model.